The Demarcation Current of Mammalian Nerve. 327 



It is obvious that the law as stated approximately represents the 

 truth in the case of NaCl and KC1 solutions. In how far the approxi- 

 mation is different in the two cases must be left to the consideration of 

 further and more exact experiments. 



That a similar law is true for solutions of HC1 is shown by the fol- 

 lowing experiments. The stock laboratory solution of 0*4 per cent. 

 HC1 was diluted twice, &c., to obtain the required variations of con- 

 centration. 



Experiments with solutions of HC1. 

 Concentration. 



In this case presuming the statement of the law to be 



then 



in Case (1.) k = - x 2-0 = (HI 



lo'J 



(2.) t - ^ x 4-0 = 0-11 



* - 



1455 



The law in this case is E n = E log 



It is obvious that in the three cases considered the concentration law 

 is amply expressed as 



E = y^.E.log- 2 , 

 n 



where k\ and k% are constants. 



The interest attached to this mode of expressing the law is seen, 

 upon reference to the theory of concentration cells, to be considerable ; 

 and the occurrence of the law cannot be otherwise regarded than as a 



2 B 2 



